Mucositis is a condition characterized by swelling, irritation, and discomfort of mucosal linings such as those of the gastrointestinal tract and the oral and oral pharyngeal cavities, and can result in mouth and throat sores, diarrhea, abdominal cramping and tenderness, and rectal ulcerations. This condition occurs in approximately half of all cancer patients undergoing therapy, and is a common side effect of cancer treatments involving radiation and/or chemotherapy. The goal of these approaches to cancer treatment is to kill rapidly dividing cancer cells but, unfortunately, other rapidly dividing cells are killed by the treatment as well, including cells that line regions such as the gastrointestinal tract, leading to mucositis.
The incidence of mucositis, as well as its severity, depends on factors such as the type and duration of the cancer treatment. Mucositis occurs, for example, in virtually all patients who are treated by irradiation of the head and neck. It is also highly prevalent in patients treated with high dose chemotherapy and/or irradiation for the purpose of myeloablation, such as in preparation for stem cell or bone marrow transplantation.
Mucositis adversely impacts the quality of life of cancer patients in several ways. For example, the mouth and throat sores of mucositis can cause significant pain and make it difficult to eat, drink, and even take oral medication. Mucositis is also accompanied by a severe risk of infection, as it can lead to a breach in the otherwise protective linings of the oral mucosa and gastrointestinal tract, which are colonized by a vast array of microorganisms. Gut toxicity is a major limiting factor in radiation and chemotherapy treatment regimes. Further, efforts to counter the discomforts of mucositis can lead to disruptions in cancer treatment, alterations in treatment dosages, or shifting to different modes of treatment. Severe mucositis can also lead to the need for parenteral nutrition or hospitalization. The development of effective approaches to preventing and treating mucositis is therefore important for improving the care of cancer patients.
Alimentary mucositis refers to a form of mucosal barrier injury to the alimentary tract. Alimentary mucositis may occur at a part or multiple parts of the alimentary tract, from mouth to anus, via, e.g., esophagus, stomach, small intestine, colon, and rectum. Non-limiting examples of alimentary mucositis are oral mucositis, esophagitis, stomatitis, enteritis, and proctitis. See, e.g., Blijlevens et al., Bone Marrow Transplant 25:1269-1278 (2000); and Keefe et al., Seminars in Oncology 20:38-47 (2004).
Alimentary mucositis are generally caused by one or more insults, most commonly by a chemical(s) or radiation, or a combination thereof. Radiation may be a result of, e.g., radiation therapy, accidental radiation exposure, and radiation exposure from a terrorist attack. See e.g., Moulder, Int. J. Radiat. Biol. 80:3-10 (2004). Chemical insults are commonly from chemotherapy.